Best debugger for DOS?

Trying to remove protection from an old DOS game I have, 'The Jetsons The Computer Game'. Trying to find a good debugger I can step through with. I can't step with IDA Pro, debug.exe is quite confusing.

First it checks the disk for certain sectors, however it is very easy to do a n00bish JMP over all of that then the game will load a COM file into memory and wait for that to terminate (and get its exit code). I can also directly launch that COM file (CMF extension). Both give the same result. JMP'ing over the floppy check might not be the way to go?

By the way, is the CMF extension a relic of any known copy protection during the DOS era?

Even if this game is cracked already, I'd really like to get this one myself.